Experimental constraints on transport from dimensionless parameter scaling studies

Journal Article · Fri May 01 04:00:00 EDT 1998 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.872838· OSTI ID:627766

Petty, C C; Luce, T C; Baker, D R; Ballet, B; Carlstrom, T N; Cordey, J G; DeBoo, J C; Gohil, P; Groebner, R J; Rice, B W; Thomas, D M; Wade, M R; Waltz, R E ^[1]

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1. General Atomics, San Diego, California92186-5608 (United States)

The scalings of heat transport with safety factor (q), normalized collisionality ({nu}), plasma beta ({beta}), and relative gyroradius ({rho}{sub {asterisk}}) have been measured on the DIII-D tokamak [Fusion Technol. {bold 8}, 441 (1985)]. The measured {rho}{sub {asterisk}}, {beta} and {nu} scalings of heat transport indicate that E{times}B transport from drift wave turbulence is a plausible basis for anomalous transport. For high confinement (H) mode plasmas where the safety factor was varied at fixed magnetic shear, the effective (or one-fluid) thermal diffusivity was found to scale like {chi}{sub eff}{proportional_to}q{sup 2.3{plus_minus}0.64} , with the ion and electron fluids having the same q scaling to within the experimental errors except near the plasma edge. The scaling of the thermal confinement time with safety factor was in good agreement with this local transport dependence, {tau}{sub th}{proportional_to}q{sup {minus}2.42{plus_minus}0.31} ; however, when the magnetic shear was allowed to vary to keep q{sub 0} fixed during the (edge) safety factor scan, a weaker global dependence was observed, {tau}{sub th}{proportional_to}q{sub 95}{sup {minus}1.43{plus_minus}0.23}. This weaker dependence was mainly due to the change in the local value of q between the two types of scans. The combined {rho}{sub {asterisk}}, {beta} , {nu} and q scalings of heat transport for H-mode plasmas on DIII-D reproduce the empirical confinement scaling using physical (dimensional) parameters with the exception of weaker power degradation. {copyright} {ital 1998 American Institute of Physics.}

• OSTI ID: 627766
• Report Number(s): CONF-971103--
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 5; ISSN 1070-664X; ISSN PHPAEN
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CHARGED-PARTICLE TRANSPORT
HEAT TRANSFER
LIMITING VALUES
SCALING LAWS
THERMAL DIFFUSIVITY
TOKAMAK DEVICES